OVERALL OBJECTIVES: The overall objective of the research to be performed during the tenure of this grant is to determine whether specific protein synthesis initiation factors, when implanted into 17 hr chick embryos, direct these embryos to develop additional embryonic structures not normally developed in the embryo at the site of implantation. To accomplish this end, we were required to accomplish the following: 1) build an in vitro protein synthesizing system, 2) purify chick embryo mRNA, 3) develop a means of extracting and testing for the presence of protein synthesis initiation factors, and 4) extract and purify embryo protein synthesis initiation factors. These goals have been only partially attained. RESULTS: We have, at present, developed a wheat embryo system for in vitro protein synthesis. In this system, heparin is capable of blocking initiation without altering elongation of already initiated peptide synthesis. Heparin, covalently linked to sepharose, can be used to strip wheat extracts of their initiation factors. The factors, removed from wheat extracts, may be released from the sepharose affinity columns at various salt concentrations (all are released at 0.5M KCl), and used to supplement the stripped wheat embryo system. We have also been able to purify 9 1/2 day chick embryo, mRNA. This mRNA, however, has only 1/10 to 1/20 the activity (as measured by H3-valine incorporation/microgram mRNA) of rabbit globin mRNA. We have not yet been able to extract chick embryo initiation factors from chick microsomes since these embryo extracts possess powerful inhibitors of protein synthesis in addition to their initiation factors. SIGNIFICANCE: The purpose of the described research is to investigate some of the biochemical control mechanisms regulating early embryonic development. Our purpose is to determine if embryonic induction is controlled in part by factors regulating the initiation of protein synthesis.